1. Field of the Invention
The present invention relates generally to a microphone apparatus, and is directed more particularly to a microphone apparatus suitable for use upon collecting sound by utilizing a sound field near the surface of a rigid body plain plate and so on.
2. Description of the Prior Art
Recently, such a sound collecting method for utilizing the sound field near the surface of a rigid body plain plate becomes a topic in the art. In case of employing such sound collecting method, it is necessary to clearly grasp the relation among the setting state, frequency characteristic, directivity at a sound receiving point and so on. As to the sound field near the surface of a rigid body plain plate analysises and experiments have been carried out in various view points by many researchers from the end of the 19th century. In order to perform severe analysis of such sound field, it is necessary to consider the diffraction of sound through one side of the surface of a rigid body plain plate to its back or rear side. However, when such severe analysis is performed, complicated calculations must be achieved. Therefore, in the prior art satisfactory results are not always obtained and hence the prior art sound collecting method utilizing the sound field near the surface of the rigid body plain plate is lacking in practice and it is difficult to provide a desired microphone apparatus for practising such sound collecting method.